My neighbor stands in his driveway, his tiny Papillon barking furiously at my dog, Sophie. “Your dog is not socialized, eh?” he says. I point out that it is his dog that is behaving aggressively toward Sophie. “But that’s because she growled at him,” he says.

I have met him several times in the morning while walking my two-year-old Shar-Pei. Each time, his little dog has rushed furiously at Sophie, barking his little head off. Each time, he has done nothing to restrain or otherwise correct his dog. In fact, he often just stops and stares, allowing his dog to continue with his aggressive behavior while doing nothing. Meanwhile, a few doors down, the owner of a Cocker Spaniel yells at his dog, who is also barking furiously at Sophie, to return home. He routinely allows his dog off the leash in his unfenced back yard, and the dog, upon seeing Sophie, immediately reacted to defend its territory.

This is standard behavior for the small dog owners in my neighborhood, I have learned. Next door to the Cocker Spaniel owner lives an older man who walks his small Maltese every morning. Whenever this dog sees Sophie, she charges at her, barking and lunging. He does nothing.

In the small, two- or three-block area where I walk Sophie, there are approximately a half-dozen owners of small or toy dogs. Almost without exception, these owners allow—and sometimes even seem to encourage—their small dogs to behave aggressively towards my dog.

When I first got Sophie, she was very friendly to other dogs she met on her walks, regardless of their size. Now, whenever she sees a small dog, she becomes agitated and starts to growl. It breaks my heart.

These small dog owners are behaving extremely irresponsibly. Not only are they allowing their own dogs to behave inappropriately, but they have now conditioned my dog to react defensively whenever she sees a small dog.

I have a theory that small-dog owners find their pets’ aggressive behavior cute, endearing and funny. They believe that because their dog is small and could never be a threat to any other dog, therefore it’s OK to allow it to growl, bark, snap and charge at my dog.

But it’s not OK.

It seems a double standard exists in the dog world between owners of small-breed dogs and owners of larger breeds. Medium-sized and large-breed owners must make sure their dog is never aggressive to other dogs, but owners of small breeds may give their dogs free rein.